gasmachine85

iTrader: (2)

i have the 1.7 ratio non adjustables....

adjustable would allow you to set your valve lash to a certain amount of preload... i have adjustable rockers in my GN..

no they do not come with lifters.

Quicklynx

Awesome. I messaged Seth at Hinson to get some recommendations.

My guess is the rev kit they have is probably a really good idea to get?

Quicklynx

I'm being told the 243s will not work because the bore is too small.

Can someone chime in on this? I'm looking at some builds with the 4.8L bore and it looks like people are using the 243 heads on them.

I just bought a block and had it shipped. I could have saved on shipping and bought the heads for it at the same time. Looks like I'll be eating shipping for some heads if I can't use the 243.

nonnieselman

iTrader: (10)

243/799s come on 4.8 and 5.3s from the factory.
Dunno why they would say that.

Quicklynx

Awesome. Thanks for the reply. I was thinking the same thing. I was told they wouldn't work by a known vendor that machines the heads and sends them out.

I seriously think the whole "small displacement" thing is not going over well with the Goat community that even the vendors don't want to help me, haha.

This is going to make this build so much more sweet.

dmelvin

iTrader: (8)

4.8 and 5.3 have the same bore. And I'm running 243 heads on my 5.3 no problem, just have to get 3.901 bore head gaskets.

TXSZ66AVLANCHE

iTrader: (7)

Part #12498544 is a set of 2 head gaskets $35 which is a stock LS1 head gasket...and its also used from the factory on NNBS 4.8 and 5.3

ForcedTQ

iTrader: (1)

Exactly, otherwise the combustion chamber will have a little bit of "gasket lip" hanging out into it.

That known vendor might be referring to how close the 2.00" intake valve will be to the bore of the cylinder, thus shrouding the valve. Look into a competition multi angle valve job to help that thing breath. Blending the valve seats into the the throats of the port making a smooth transition to the radius in the port, keeping consistent volume in the port to keep velocity up would be a good idea. From what I have read on here there is no need to even think about increasing the port "size" as hogging it out is just going to screw up the flow characteristics of the whole assembly. Also no reason to be "porting/polishing" the combustion chamber and as a result increasing the combustion chamber volume (lower static compression) as you're already going to be pretty low as it is. Take a look at running a little bit thinner than stock head gasket to bump that compression up a hair. Think about how much you're willing or not willing to have the head decked. Alot of guys on here run 243/799's with .030" removed, but you also have to remember that's taking material away, which could be a concern to my thought below.

You are adding a turbo to this as well correct? Think I read that in another thread. I know someone already said this, but I'm going to say it again. Coatings, thermal barrier specifically. Combustion chamber, intake valve face, exhaust valve face and back side, exhaust port, and piston top. That'll help keep the heat where it needs to be making the most of the combustion event. I have also heard of the intake port / valve back side being coated with a oil/liquid shedding material that helps keep the ports clean (from PCV fumes/fuel varnish) and fuel atomization to some extent.

dmelvin

iTrader: (8)

Didn't even think about the NNBS. But they're running 243/799 heads, so that definitely makes sense.

Quicklynx

Would these be fine for forced induction? Like you all have been saying I'd like to up the compression a bit.

Yes. I'm going to go twin turbo. I plan to deck the block and heads to get them matched. Any recommendations on head gaskets? I'm going to give them my head gaskets to machine as well when they start doing my build.

They are going to do all the machining. I plan to do all the cleaning, pre assembly, final assembly, etc..

Thanks for the info on the heads. yes I want to keep the compression up above 9:1, or higher if I can, below 10:1.